1. Field
The present application relates to a data processing technique that makes data search easy.
2. Description of the Related Art
In the recent information society, various types of data such as images and audio are utilized. In particular, these types of data are utilized frequently by converting original data to generate new data. For example, taking image data of an electronic camera as an example, raw image data (RAW data) read out from an image sensor is converted into easily-handled JPEG data for use. Although the JPEG data is image data which has a small data size and can be handled easily compared to the RAW data, since the data size of an image is compressed to a data size of the minimum requirement, there is a problem that a gradient is lost easily when exposure, chroma, contrast, etc. of an image are adjusted using this JPEG data.
Accordingly, there is an electronic camera capable of storing the JPEG data and the RAW data which is the original of the JPEG data, as a JPEG file and a RAW file, respectively. In such an electronic camera, it is possible to read out the RAW file which is little degraded when the image adjustment of exposure, chroma, contrast, etc. is carried out according to a display device or a printer to be used, and to use the JPEG file when the image adjustment is not necessary.
However, when the image adjustment without the image quality degradation is required while an image of the JPEG file is displayed, it is necessary to carry out searching for the RAW file from which the JPEG file has been generated. For this purpose, it has been devised conventionally that the original RAW file can be identified from the JPEG file by providing the both files with the same file name but different extensions, or by storing the both files into the same folder in order to find the RAW file easily from the JPEG file.
Meanwhile, there is devised a method to utilize the JPEG file in which verification data is added to the JPEG data so as to identify the JPEG file, although it is originally devised for determining whether the data is modified or not (refer to, e.g., Japanese Unexamined Patent Application Publication No. 2005-184046).
However, there arise problems as follows in the conventional method which retains the JPEG file and the RAW file always in the same folder. First, when the JPEG file and the RAW file are stored in the same folder, the number of files is doubled compared to the number of image shootings and there arises a problem that file handling has vexatious complication, as images of the same shooting are displayed redundantly for file display of the folder or for display using image browser software.
Further, when an image of the same shooting is used in a plurality of folders, it is necessary to store the same JPEG files and RAW files into different folders redundantly, and there arises a problem that a memory size of a storage medium becomes huge.
For avoiding such problems, it is devised to search the RAW file when required, by storing the RAW files into a predetermined folder in one lump, without retaining the daily used JPEG file and the RAW file in the same folder.
However, for carrying out such searching, it is necessary to relate the JPEG file and the RAW file of the simultaneous shooting to each other. For example, if every image data is shot with the same digital camera, it is possible to carry out the shooting in a setting to make the file number to be a sequential number, and to search for the RAW image file using this information, but if the file name of the JPEG file is altered, there arises a problem that the search cannot be carried out. Moreover, when handling images shot by two or more kinds of digital cameras, it is difficult to administrate the images by the file names.
Alternatively, when the search is carried out for the simultaneously shot RAW image file from the JPEG image file, it is possible to carry out the search by referring to meta data such as a shooting date and time and information of the used camera, not by the file name. For a camera capable of high-speed consecutive shooting, however, it is necessary to store the detailed shooting date and time for distinguishing the file name, resulting in requiring a high precision storing means and increasing a data size to be stored. Further, when the search is carried out by referring to the meta data, there are various types of search information and it is a problem that the search processing has vexatious complication.
In this manner, a new technique is expected which administrates the RAW file in one lump and also searches for the RAW file of simultaneous shooting easily from the JPEG file. Note that, not limited to the image data, master data is necessary also for audio data when audio quality is desired to be changed by an equalizer or echo processing. Further, when general data is handled for software development which requires version management, there is also a case where it is necessary to refer to original data while data derived from the original data is used and there arises a problem similar to that in the case of the image data.